Originally Posted by
Benelli B76
Dave, I am interested that you say the piston seal is PTFE as this material is soft and malleable and would change shape when hitting the end of the cylinder. Most piston seals are polyurethane which is tough and hard wearing.People have experimented with PTFE seals and find they extrude into the transfer port. I think the only area you could use PTFE is in a piston ring seal where there is no impact, so is your material a harder compound mix ? Would be interesting as urethane is not the easiest to turn complex shapes on the lathe.
Baz